Grit Index: D-backs' struggles continue against last-place Padres

San Diego Padres' Yonder Alonso, center, gestures after hitting a two-run home run against the Arizona Diamondbacks in the fourth inning during their baseball game Friday, May 3, 2013, in San Diego. Arizona Diamondbacks catcher Miguel Montero, left, and home plate umpire Mike DiMuro, right, look on. (AP Photo/Gregory Bull)

For the second consecutive outing, Arizona Diamondbacks left-hander Wade Miley couldn't seem to find any rhythm.

While Miley was able to make it through five innings Friday night, the Padres touched him up for four earned runs, including a go-ahead two-run shot by Yonder Alonso in the fifth inning.

The D-backs offense got a jolt from Gerardo Parra in the ninth inning with a three-run shot, but the Padres tacked on three additional insurance runs off Josh Collmenter and Brad Ziegler in the seventh and eighth innings en route to a 7-6 win.

Arizona has lost a season-high four straight games.

The Good:

Eric Chavez continues to produce when given the starting nod. The D-backs third baseman has at least one hit in each of his last seven starts. In the span, he also has five RBI, including Friday's run-producing single.

Miguel Montero also hit his first home run in over a month, a solo shot off Jason Marquis in the second inning.

The Bad:

Miley's command of the strike zone wasn't as big of an issue as it was last Saturday, but he allowed at least one base runner in all five innings of work.

While Alonso's home run proved to be the difference, it might never have been if not for shortstop Cliff Pennington's inability to turn a tailor-made double play one batter earlier.

Stat of the Game:

Seven. A D-backs starting pitcher hasn't won a game in seven straight appearances dating back to April 25 when Trevor Cahill beat the Colorado Rockies.

Noted:

• Reliever Matt Reynolds made his 11th straight appearance without giving up a run. He's allowed just six hits in 16 innings of work.

• Didi Gregorius, who is currently on the seven-day disabled list with concussion symptoms, is expected to be activated for Saturday night's game.

Up Next:

The D-backs will look to snap their four-game losing streak Saturday when Patrick Corbin (3-0, 1.91) takes the bump against the Padres. He'll be opposed by San Diego left-hander Clayton Richard (0-3, 7.94). First pitch is scheduled for 5:40 p.m. and can be heard on Arizona Sports 620.